Present methods and apparatus used to practice the conventional Air Carbon Arc Cutting and Gouging Process involved the melting of a metal workpiece by an electric arc and blowing away of the molten metal with a high velocity jet of air applied under pressure from a source such as a compressed air supply. Although this is a fast and efficient process, it presents environmental problems associated with spraying of the molten metal into the surrounding areas and generation of fumes consisting primarily of metal oxides of the metal being worked on. Extremely high noise levels are produced, usually in the range of 115-125 DbA which are above the accepted industry standards for operator exposure without the use of noise protection equipment.
A U.S. Pat. No. 4,527,037 discloses and claims an automatic Air Carbon-Arc Cutting and Gouging Torch that is a standard in the industry. The device of the '037 patent is usable in the present invention and the specification of the '037 patent is incorporated herein by reference for the disclosure of the device as well as for a discussion of the Air Carbon-Arc Cutting and Gouging Process in general.
In the past in order to control the problems associated with the Air Carbon-Arc Metal Removal Process the metal spray inherent in the process has usually been controlled by erecting barricades or enclosures around the work area where the cutting or gouging work is being performed. The same effect can be obtained by merely isolating the work area from other workers. The fume generation problem associated with the Air Carbon-Arc Cutting and Gouging Process is usually handled by suitable ventilation of the work area where the fumes are collected with a suction device incorporating filtration systems. These latter devices are usually large and correspondingly expensive in order to cope with degree of particulate levels produced. Collection devices used with the torch have been tested at various times in the past in an attempt to collect the molten metal spray produced by the process, but have usually failed after short time due to damage caused by hot metal striking the internal components of such systems. These devices, when not destroyed, soon become clogged with solidified metal and soon cause unacceptable system operational delays.
One attempt to solve this problem is detailed in U.S. Pat. Nos. 4,338,514 and 4,502,179 both of which are owned by the assignee of the present invention. The device of the '514 and '179 patents utilized a cumbersome hood and evacuation system in order to minimize the metal spray and fume generation problems. The use of insulation in the cumbersome hood of these devices also helped to reduce the magnitude of the process generated noise. The specifications of the '514 and '179 patents are also incorporated herein by reference.
Thus no significant solution to the noise generation problem has been incorporated into conventional Air Carbon-Arc Cutting and Gouging process equipment. Therefore, personal protection devices such as ear plugs are generally used by operators to minimize the effect of the high noise levels generated when using the air carbon-arc process. Furthermore, large enclosure are utilized as noise barriers to eliminate the noise transferred to the surrounding areas.